A.15~18mm B.18~20mm C.18~25mm D.25~30mm E.30~35mm
A.伸舌吞咽 B.咬物習(xí)慣 C.乳牙早失 D.偏側(cè)咀嚼 E.遺傳因素
A.可用間隙 B.靈長間隙 C.替牙間隙 D.發(fā)育間隙 E.必須間隙